在 C 上使用 WPF 控制台发送电子邮件#

问：

我正在尝试在 C# （.NET 6.0） 上构建 WPF 应用程序。 这个应用程序必须发送邮件。我给出的参数是：mailFrom、mailTo、host、password、subject 和邮件正文。响应按钮“发送”的类是这样的：

public partial class MainWindow : Window
{
    private readonly ILogger<MainWindow> _logger;

    public MainWindow()
    {
        InitializeComponent();
    }

    public MainWindow(ILogger<MainWindow> logger) : this()
    {
        _logger = logger;
    }

    private void btnSender_Click(object sender, RoutedEventArgs e)
    {
        MessageRequest mailRequest = new MessageRequest();

        var builder = new BodyBuilder();

        mailRequest.ToEmail = tbReceiver.Text;
        mailRequest.FromEmail = tbSender.Text;
        mailRequest.Subject = tbSubject.Text;
        mailRequest.Body = tbMessage.Text;
        mailRequest.Host = tbHost.Text;

        SendMail(mailRequest, builder);
    }

    private void SendMail(MessageRequest mailRequest, BodyBuilder builder)
    {
        var email = new MimeMessage();

        email.From.Add(MailboxAddress.Parse(mailRequest.FromEmail));
        email.To.Add(MailboxAddress.Parse(mailRequest.ToEmail));
        email.Subject = mailRequest.Subject;
        email.Sender = MailboxAddress.Parse(mailRequest.FromEmail);

        builder.HtmlBody = mailRequest.Body;
        email.Body = builder.ToMessageBody();

        using var smtp = new SmtpClient();

        smtp.CheckCertificateRevocation = false;

        smtp.Connected += Smtp_Connected;
        smtp.Authenticated += Smtp_Authenticated;
        smtp.Disconnected += Smtp_Disconnected;
        smtp.MessageSent += Smtp_MessageSent;

        if (!IsValidEmail(email.From.ToString()) || !IsValidEmail(email.To.ToString()))
        {
            _logger.LogError("ERROR: Mail not valid.");
        }
        else
        {
            smtp.Connect(mailRequest.Host, 587, SecureSocketOptions.StartTls);

            if (true)
            {
                smtp.Authenticate(email.From.ToString(), "XXX");
            }

            smtp.Send(email);
        }            

        smtp.Disconnect(true);
    }

    private void Smtp_MessageSent(object? sender, MessageSentEventArgs e)
    {
        _logger.LogTrace("Message sent {message}. Response: {response}", e.Message, e.Response);
    }

    private void Smtp_Disconnected(object? sender, DisconnectedEventArgs e)
    {
        _logger.LogTrace("Disconnected to SMTP {host}", e.Host);

    }

    private void Smtp_Authenticated(object? sender, AuthenticatedEventArgs e)
    {
        _logger.LogTrace("Authenticated to SMTP host");
    }

    private void Smtp_Connected(object? sender, ConnectedEventArgs e)
    {
        _logger.LogTrace("Connected to SMTP {host}", e.Host);
    }
    private bool IsValidEmail(string email)
    {
        try
        {
            var mailAddress = new System.Net.Mail.MailAddress(email);
            return mailAddress.Address == email;
        }
        catch
        {
            return false;
        }
    }
}

但它返回以下错误： 'System.ArgumentNullException： 'Value 不能为 null。Arg_ParamName_Name'。我发现问题出在记录器不起作用并返回此错误。我注释代码行：smtp.Connected += Smtp_Connected; smtp.Authenticated += Smtp_Authenticated; smtp.Disconnected += Smtp_Disconnected; smtp.MessageSent += Smtp_MessageSent;

现在它起作用了。但是，如果我编写相同的代码，但仅适用于 Web API，如果我不注释这些行，它也可以工作。解决方案是什么？